Quoting Oriane

Well done, Gargoyle- this article just about covers what’s out there. The 23rd date I had also read- it is the European release date- but no one would explicitly tie the two together.

Yeah, I couldn't find anything official that says it will be out on the 23rd, either. I wouldn't be surprised if Sony had the new firmware available on the 23rd, though, so that new European owners can get updated firmware right away. Of course, there's nothing that says they have to give the update to the rest of the world the same day. Sony is probably plenty busy getting PS2 emulation ready for the Euro release.